Revealing mistake: The background scenery in the outdoor shots doesn't look anything like Illinois, where the movie's supposed to be set. It's much more like what you'd see in California - where the actual filming took place.
Continuity mistake: When Monica and Steve are in Monica's classroom, the position of her hair changes from being over one shoulder, to being over two shoulders as the shots change from being in front of her and behind her.
Continuity mistake: After "A Lovely Night," while Cinderella and her stepmother are talking, Cinderella's hair keeps moving- sometimes there's more hanging in front of her shoulder, sometimes there's more in back.
Plot hole: In the waning seconds of the championship game, the Huskies are down by 2 and UMass has the ball. Not only do the Huskies not intentionally foul to stop the clock, but UMass attempts to run a play and set up a basket when they simply could have dribbled out the clock and won the game. Both these strategies go against what any basketball team would do in this situation, especially in a championship game.
Continuity mistake: There's Fall foliage at the beginning of the movie and when Bokky [Bill Paxton] and Pat [Mark Wahlberg] are leaving the camp grounds but, after they drive away, the foliage is Summer-like (and varies thereafter). (00:19:50)
Plot hole: Marcus told Melena he lived in New Mexico with his parents until he was 5 years old: "My dad died in a car accident when I was five... and my mom got caught smuggling people into the country, so she got 10 years [in prison]." Even though Marcus did not know at the time the real reason his mother was in prison, the murder must have occurred in New Mexico, so it doesn't make sense that she would be serving time in a New York prison. (00:33:20 - 00:34:21)